Imagine a camera, about as big as your thumb up to the first joint, wandering around the inside of your body. I swallowed one today. It immediately took two photos a second, and continued to do so for seven hours, transmitting them to a receiver that I wore on my belt and lugged around for seven hours, together with electrodes and masses of leads.
A capsule endoscopy looks for nasties in the small bowel, which can’t be seen by the more common endoscopy or colonoscopy. Over several weeks a computer and a person/s will review each of 50,000 photos and report to my gastroenterologist, who has ordered the test as a precaution when other tests showed no reason for an iron deficiency.